Sunday, December 18, 2016

From time to time the level shift module pictured above has come in handy. They do a great job shifting 3.3VDC to 5VDC logic or 5VDC logic to 3.3VDC logic. The cost is about $1USD and hookup is simple. Of course they are designed for low speed digital signals but, we wondered how the module would handle higher speeds.

Performance was very good, especially considering these module are often used in the 100KHz and below range. Leveling from 5V to 3.3V had better results. The signals start looking ridiculous over 1MHz. Take a look at the scope shots below.

Thursday, December 1, 2016

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The ESP8266 modules are so cheap who could resist experimenting with one. For about $8USD a few things you get are 9 GPIOs, I2C/SPI support, an ADC, and on board WiFi or other goodies. In addition it's all programmable in the Arduino IDE that is familiar to many and has a good user support network.

This example application shows a quick and easy way to get a portable 'WarDriver' with the WiFi ESP8266 and an OLED display.

No resistors, etc. needed; connect it up like this:

Pinout Connections

ESP8266OLED

3VDC<<==+==>>Vcc

GND<<==+==>>GND

SCL(5)<<==+==>>SCL

SDA(4)<<==+==>>SDA

Take a look at the source code below for the links on installing ESP8266 capability to the Arduino IDE. Chances are if you are reading this you already have the Arduino IDE installed; just make sure you are running at least Rev 1.6.8. Then upload the source code to the ESP8266 and your up.

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Here is a sample of the rig running in a random parking lot a fair distance from an apartment complex. Eight networks were found; all encrypted. The OLED displays the number of networks, SSID name, signal strength (dBm), and if the network is OPEN or Encrypted.

One thing that was a surprise is how many cars have OPEN WiFi running. Also, pretty much every long haul 18 wheeler heading down the interstate is a rolling WiFi hotspot, but most (not all) are Encrypted.